Field of the Invention
This invention relates to fuel injection valves for internal combustion engines, and more particularly to an outwardly opening type fuel injection valve for gasoline engines.
Description of the Prior Art
In manifold injection type internal combustion engines, particularly those fueled with gasoline, the injected spray adheres to the wall of the manifold and the atomization of the fuel is not assured, thus causing an increase in the quantity of hydrocarbons in the exhaust gas so that such manifold injection type fuel injection valves are not desirable. Further, where fuel injection valves inject directly into the cylinder, the injected spray adheres to the cylinder wall, and since the temperature of the cylinder wall is relatively low, the fuel adhering to the cylindrical wall is difficult to burn and causes an increase in the quantity of hydrocarbons in the exhaust. Thus, fuel injection valves injecting directly into the cylinders are undesirable for these reasons.
On the other hand, in order to promote the atomization of the fuel, there is provided a device wherein an air chamber is formed at the discharge end of an open injection nozzle and an air throttle is provided at the outlet of the air chamber. In this type of device, however, since the velocity is increased for atomization at the throttle portion, there is the drawback that the desirable point of arrival of the injected spray is such that the travel distance can not be shortened.
In the present invention, an air vortex chamber which generates a whirlpool or vortex action by movement of the air, is provided at the discharge end portion of the valve body which valve opens under application of fuel pressure, thus causing the fuel to hit on the inner wall of the air vortex chamber, and the fuel is carried on the air vortex whereby atmoization of the fuel is improved, and furthermore, the injection speed is decreased, thus the drawbacks which are intrinsic to the conventional outwardly opening type fuel injection valve is eliminated.